1. Field of the Disclosure
The present disclosure relates to turn signal switch devices each including an operation lever configured to be turnable from a neutral position to at least a left-turn-indicating position and a right-turn-indicating position, and in particular to a turn signal switch device in which the operation lever automatically returns from the left-turn-indicating position or the right-turn-indicating position to the neutral position when a steering wheel having been turned in one direction is turned in the reverse direction.
2. Description of the Related Art
A turn signal switch device is provided at the driver's seat of an automobile and includes an operation lever that is turnably attached to a housing that is attached to a steering column. A switch that is driven when the operation lever is turned is provided in the housing so that, when the operation lever is turned from a neutral position to a left-turn-indicating position or a right-turn-indicating position, a corresponding one of a left-turn indicator lamp and a right-turn indicator lamp blinks.
The housing has a cam surface on the inner side thereof so as to guide the operation lever that is turned. When the operation lever is turned, a driven member is driven to slide along the cam surface. The operation lever is latchable at the left-turn-indicating position and at the right-turn-indicating position. The turn signal switch device includes a cancel mechanism. In the cancel mechanism, when the steering wheel having been turned in an intended direction is turned in the reverse direction, the operation lever automatically returns to the neutral position from a corresponding one of the left-turn-indicating position and the right-turn-indicating position. An exemplary turn signal switch device including such a cancel mechanism is disclosed by Japanese Unexamined Patent Application Publication No. 10-269901.
The cancel mechanism of the related-art turn signal switch device includes a first lever member that is advanceable to a position over and retractable from a turning locus of a cancel projection that is configured to turn together with a steering shaft. The first lever member is configured to be advanceable/retractable and turnable in conjunction with the turning of an operation lever and the turning of the cancel projection, enabling the operation lever to automatically return to the neutral position. The related-art turn signal switch device also includes a second lever member configured to operate in conjunction with the cancel projection. The second lever member is supported in such a manner as to be advanceable toward/retractable from and turnable with respect to the first lever member, which is turnably supported by a housing. Therefore, the device includes an increased number of components, making it difficult to reduce manufacturing costs of the device.
In the cancel mechanism, the second lever member needs to be elastically urged constantly toward the cancel projection. The related-art turn signal switch device employs a helical torsion spring as an elastic urging member. The helical torsion spring extends from an inner peripheral portion of the housing toward the second lever member. Therefore, a space for the helical torsion spring needs to be provided inside the housing, making it difficult to reduce the size of the housing.